The invention relates to a locking device for locking a movable component, in particular a superposition drive of a superimposed steering system of a motor vehicle.
In operation of a locking device of a superposition drive unwanted noise can be generated, in particular when a locking element of the locking device is moved into a locking or a release position (i.e. into one of its end positions), so that for locking a rotating drive of the superposition drive the locking element can mechanically be brought in engagement with the same or the rotating drive can be released. The development of noise can be caused both by the locking element reciprocated between the locking position and the release position and by components which drive the locking element. What can be particularly disturbing is noise in the direct hearing range of a person (in its direct vicinity), as it can be produced for example in a superposition drive arranged in a steering wheel of a motor vehicle. The problem of the generation of noise does of course not only exist during locking of a superposition drive, but it generally arises during locking of a movable component, e.g. also during locking of a linearly moving component.
From DE 10 2010 037 384 A1 there is known a locking apparatus for a superposition steering system with an electromagnetic actuator. The latter drives a locking pin serving as locking element. To avoid a direct mechanical contact between the locking pin and other components of the actuator, elastic O-rings are provided in the end positions of the locking pin. In such arrangement it is disadvantageous that the O-rings merely provide a small deformation path, which imposes certain limits on a design of the course of force during braking of the locking element. The use of air or oil dampers, which furthermore is proposed in the above-mentioned document, is expensive. The space requirement also can be high, which especially in the case of superposition drives arranged in the steering wheel can lead to installation space problems.